Parameters

The PreviewMouseLeftButtonUp event appears to travel a tunneling route but actually travels in an indirect way. Mouse.PreviewMouseUp is the underlying event that is tunnel routed, and each UIElement along the event route uses identical handling to raise the direct routed event PreviewMouseLeftButtonUp. Although you can mark the PreviewMouseLeftButtonUp event as handled for purposes of this element, the handled state does not perpetuate to other elements along the event route. However, you might want to mark the event as handled in order to prevent general instance handlers (those that did not specify handledEventsToo) from being invoked.

The default implementation for general mouse event handling in UIElement listens for Mouse.PreviewMouseUp and converts it to an appropriate local event. If you want to override this logic, you must create a derived class. In the static constructor of your derived class, register an alternative class handler for Mouse.PreviewMouseUp. You cannot change the mouse handling behavior of UIElement by overriding OnPreviewMouseLeftButtonUp.